Elongated belt retractor and stop means

ABSTRACT

An elongated belt-locking retractor includes a support on which is mounted a pair of elongated toothed racks and a slide which reciprocates on the support between the racks. The slide has pawls which in an extended position mate with the racks but which are normally retracted against a stop by a spring. A cam for driving the pawls into the racks is mounted to the slide for motion with or motion relative to the slide depending on the differential rate of acceleration between the cam and the slide. A belt passes around the cam and acceleration of the belt accelerates the cam as the belt moves. If the rate of acceleration is less than a predetermined rate, the cam and the slide reciprocate as a unit allowing the belt to move freely. If the rate of acceleration is greater, the cam moves relative to the slide, driving the pawls into the racks to lock the slide and thereby lock the belt.

United States Patent [72] lnventor Akira Tanaka Northridge, Calif. [2!]Appl. No. 798,594 [22] Filed Feb. 12, 1969 [45] Patented Jan. 26, 1971[73] Assignee General Motors Corporation Detroit, Mich. a corporation ofDelaware [54] ELONGATED BELT RETRACTOR AND STOP MEANS 6 Claims, 7Drawing Figs.

[52] U.S. Cl 188/134, 188/82.7:297/386 [51] lnt.Cl B60f7/12 [50] FieldofSearch 188/823, 7,134, 135; 297/386 [56] References Cited UNITEDSTATES PATENTS 2,953,315 9/1960 Lautier et a]. 297/386X 3,288,254 11/1966 Replogle Primary Examiner-George E. A. Halvosa Attorney E. W.Christen and Herbert Furman ABSTRACT: An elongated belt-lockingretractor includes a support on which is mounted a pair of elongatedtoothed racks and a slide which-reciprocates on the support between theracks. The slide has pawls which in an extended position mate with theracks but which are normally retracted against a stop by a spring. A camfor driving the pawls into the racks is mounted to the slide for motionwith or motion relative to the slide depending on the differential rateof acceleration between the cam and the slide. A belt passes around thecam and acceleration of the belt accelerates the cam as the belt moves.If the rate of acceleration is less than a predetermined rate, the camand the slide reciprocate as a unit allowing the belt to move freely. Ifthe rate of acceleration is greater, the cam moves relative to theslide, driving the pawls into the racks to lock the slide and therebylock the belt.

PATENTED JAN26 I971 SHEET 1 OF 2 INVENI'UR A T TURN/FY PATENIEUJAN26I971 8.557314 SHEET 2 [IF 2 INVENI'UR.

A T TORNEY ELONGATED BELT RETRACTOR AND STOP MEANS This inventionrelates to a retractor for a restraint belt and more particularly to anelongated belt retractor having inertia locking. Various elongatedrestraint belt retractors with a locking mechanism responsive to beltacceleration have been proposed. However, these retractors rely mainlyon the opposition of the force of gravity for locking action. In avehicle, this reliance has disadvantages under the varying operatingconditions.

The elongated retractor of this invention uses the acceleration of arestraint belt for camming pawls into locking engagement with toothedracks to lock the belt. The locking action is not dependent of the forceof gravity and is, therefore, operable under varying conditions.

Thus, it is an object of this invention to provide an elongatedretractor for a restraint belt which will operate under varying inertiaand gravity forces such as those found in a vehicle. It is anotherobject of this invention to provide an elongated retractor for arestraint belt which operates by restraint belt acceleration. It is afurther object of this invention to provide an elongated retractorhaving locking means operated by belt acceleration. It is still anotherobject of this invention to provide an elongated retractor having racksto which pawls operated by belt acceleration are locked. It is still afurther object of this invention to provide an elongated retractor whichhas a plurality of racks, and pawls which simultaneously lock to theirrespective racks to equally distribute the locking load. It is yet afurther object of this invention to provide an elongated retractor whichwill operate dependably and repeatedly under all conditions found in amotor vehicle.

In accomplishing these objects, the retractor generally includes a pairof racks between which a slide moves as a restraint belt is moved. Theslide has a pair of movable pawls which normally do not engage theirrespective racks but which at a predetermined rate of belt acceleration,are driven into their respective racks by a cam to lock the slide andthe belt against further movement.

These and other objects of this invention will become apparent from thefollowing detailed description taken in conjunction with theaccompanying drawings wherein:

FIG. 1 is a partial perspective view of a vehicle body having anelongated belt retractor, according to this invention, mounted in theroofside rail thereof.

FIG. 2 is an enlarged partially cutaway view of the retractor with thepawls permitting free movement of the restraint belt.

FIG. 3 is a sectional view taken substantially along the line 33 of FIG.2.

FIG. 4 is a sectional view taken substantially along the line 4-4 ofFIG. 2.

FIG. 5 is a view similar to FIG. 2 with the pawls locked to the rackspreventing movement of the restraint belt.

FIG. 6 is a partially cutaway perspective view showing the slide, pawland cam.

FIG. 7 is a partially cutaway view of another embodiment of thisinvention.

Referring now to FIG. 1, a conventional vehicle body 10includes aconventional shoulder belt 12 having one end attached to an elongatedretractor 14 according to this invention. Retractor 14 is attached bysheet metal screws 16 to the roof side rail 18 body 10. The other end ofthe belt 12 is releasably attached to a mating conventional restraintbelt 20, by a conventional buckle 22.

Referring now to FIGS. 2 through 6, the retractor I4 includes anelongated support 24 having a central channel 26 and two outwardlyextending flanges 28 and 30 running the entire length of the support 24.Mounted to the flanges 28 and 30 by any conventional means such as thescrews 16 shown in FIG. 3, are a pair of toothed longitudinal racks 32.Placed in channel 26 of support 24 for movement between the racks 32 isa slide 34 of nylon or other material which slides easily. As shown inFIG. 3, the slide 34 includes a flat plate portion 35 and two laterallyextending runners 36. The runners 36 engage the sides and bottom of thechannel 26 to guide the path 0f slide 34 along the channel without anycocking movement though there may be inertia forces on the slide 34tending to cock the slide in the channel 26. The runners 36 also spacethe plate portion 35 of the slide from the bottom of channel 26 in orderto permit the belt I2 to pass under the slide.

Pivotally mounted to the right-hand end of a plate portion 35 bypartially threaded bolts 38 are one end of each ofa pair of pawls 40.The pawls 40 each have edge teeth 42 on the other end. The teeth 42 matesquarely with the teeth of a respective rack 32 when the pawls 40 arepivoted outwardly towards the racks. On the opposite edge of the pawls40 from the teeth 42 are camming surfaces 44 which are shaped so thatany pressure against them will pivot the pawls 40 outwardly and engageteeth 42 with the teeth of the racks 32. Each of the pawls 40 has a hole46 into which is inserted one end ofa tension spring 48 to bias thepawls 40 together and into engagement with a lateral stop 50, protrudingfrom the plate portion 35 to normally keep the teeth 42 out ofengagement with the teeth of the racks 32.

A cam 52 has a right-hand flat portion 54 which si slidably seated onplate portion 35 between runners 36. Portion 54 includes cam surfaces 56and a slot 58, of a length later to be described, centrally locatedbetween the cam surfaces. A partially threaded bolt 60 through slot 58,slidably mounts the flat portion 54 on plate portion 35, with the camsurfaces 56 nearly engaging or engaging surfaces 44 of the pawls 40 whenthe right-hand end of slot 58 is against bolt 60. The bolt 60 istightened to obtain a predetermined degree of frictional engagementbetween the lower surface of the portion 54 of the cam 52 and the uppersurface of the plate portion 35 of the slide 34. The purpose of thisfrictional engagement will be later described.

The flat portion 54 of cam 52 also has spaced downwardly extendingrunners 62 at its left-hand end as best shown in FIG. 6. These runners62 engage channel 26 and fit between the runners 36 of slide 34 tosupport and space the cam 52 from the channel 26 and complete the threepoint support of the the cam.

Also near the left-hand end of cam 52 are upwardly extending aperturedsupports 64 which are formed from the material of an opening in this endof the cam. Mounted between the apertured supports 64 by pin 66 is aroller 68.

A spring-driven reel 70 is rotatably mounted on support 24. A flexiblewire 72 is attached at one end to the reel and wound about it, while theother end is affixed to the left-hand end of cam 52 by pin 74. The reelnormally maintains the right-hand end of slot 58 against bolt 60 andbiases both the cam 52 and the slide 34 towards the left as shown inFIG. 2.

The support 24 has three slots 76, 78 and 80 in the righthand end ofchannel 26 as shown in FIG. 2. The one end of belt 12 is passed downthrough slot 76, up through slot 78, down through slot 80 and thenwrapped back on itself. The one end of belt 12 is stitched to the beltbehind channel 26 between slots 76 and 78 to anchor the belt to theretractor 14. The other free end of the belt extends from the slot 76along channel 26, passes under the slide 34 and cam 52 around roller 68,and then passes over the slide 34 and cam 52 and exits from theretractor at the right-hand end thereof.

Encasing the belt 12 is cover 82. The cover 82 is of a shape similar tosupport 24 and is attached thereto by the screws 16. The cover 82encloses the slide 34, cam 52 and pawls 40 as well as providing an outerguide surface for runners 36 and supports 62. The occasional engagementof the cover 82 by the runners 36 and supports 62 insures the spacing ofthe cam 52 and the slide 34 away from the cover 82 permitting the belt12 to pass unrestricted therebetween. Over cover 82 is a decorativecasing 84 which decoratively covers the retractor 14.

The normal position of the retractor is shown in FIG. 2. In thisposition the spring reel 70 maintains the right-hand end of slot 58against bolt 60 and spring 48 holds the pawls 40 against stop 50 tolocate the teeth 42 out of engagement with the rack teeth. With theteeth 42 out of engagement with the rack teeth, the slide 34 and the cam52 are free to move along the racks 32 except for the biasing force ofspring reel 70.

When the belt 12 is pulled out of the retractor, the rate ofacceleration of the belt is transferred to the cam 52.

It will be remembered that the surfaces 56 of cam 52 are nearly engagingor engaging surfaces 44 of pawls 40. If the surfaces 56 are nearlyengaging surfaces 44, and the rate of ac celeration of the belt 312 isvery low, the inertia of the slide 34 is insufficient to overcome thefriction between the engaging surfaces of the cam 52 and the slide 34,so that the cam 52 and the side 34 accelerate together with no relativemotion. If the acceleration of the belt 12 is higher but not higher thana predetermined rate, then the inertia of the slide 34 is sufficient toovercome the friction, and the cam 52 will move to the right relative tothe slide 34 until the surfaces of the cam 52 and the slide 34 engage.However, this acceleration of the belt will not be high enough toovercome the tension of spring 48 holding the pawls 40 from being wedgedapart by cam surfaces 56 and this tension will prevent further relativemotion between the cam 52 and the slide 34. If the surfaces 56 of cam 52engage surfaces 44 of the pawls 40, then the friction between theengaging suiface of the cam 52 and the slide 34 and the tension of thespring 48 acting through pawls 40 will combine to prevent relativemotion between the cam 52 and the slide 34, as the belt 12 acceleratesbelow a predetermined rate.

Without this relative motion, the pawls 40 remain against the stop 50out of engagement with the rack 32 as shown in FIG. 2 and both the cam52 and the slide 34 reciprocate within the retractor 14 as the belt 12moves against the pull of the spring reel 70'. When the belt [2 isreleased, the spring reel 70 will draw the belt back into the retractorl4 and return the cam 52 and the slide 34 to the position shown in FIG.2.

When the belt 12 is pulled out of the retractor above a predeterminedrate of acceleration, a different reaction is obtained between the cam52, the slide 34 and the pawls 40. The rapid acceleration of the belt 12is applied to the cam 52 which moves to the right. The slide 34 alsobegins to move to the right but because of its inertia will notaccelerate as rapidly. The difference in the rate of acceleration of theslide 34 and the cam 52 moves the cam 52 to the right relative to theslide 34 against the friction between the engaging surfaces of cam 52and slide 34 and against the tension of spring 48 holding the pawls 40from being wedged apart by the cam surfaces 56 as before explained.However, now the differential rate of acceleration is sufficient toovercome resisting forces of friction and spring tension and relativemovement between the cam 52 and the slide 34 begins with the camsurfaces 56 acting on pawl surfaces 44 to wedge the pawls 40 apart to aposition where pawl teeth 42 catch with the teeth of rack 32. As theteeth 42 catch the rack teeth, they stop the slide 34 from furthermovement to the right, while for a short time thereafter, the cam 52continues to move to the right, wedging the teeth 42 further into theracks 32 until they are completely engaged therein. When the teeth arefully engaged in the rack, the outward wedging action of cam surfaces 56on pawl surfaces 42, becomes an inward locking action of pawl surfaces42 to cam surfaces 56 as the pawls 40 can no longer spread. The slot 58is of such a length that the pin 60 will not engage the left end of theslot 58 until the pawls 40 have been wedged apart further than the racks32 will permit, insuring that the load of stopping the cam is on thepawls 40 rather than on pin 60. The wedging action, once the pawls 40have engaged the rack 32, continues whether the cam 52 is acceleratingor decelerating just as long as it moves to the left. Thus, as shown inFIG. 5, the slide 34 is locked to the rack 32 and the cam 52 is stoppedin turn stopping the belt 12 from further movement out of the retractor14.

This locking action holds the belt l2 against movement until the forceon the belt 12 is released, allowing the reel 70 to move cam 52 to theleft, to the position shown in FIG. 2, enabling the spring 48 to unlockthe pawls 40 from the racks. After the pawls are returned to theposition in FIG. 2, the slide 34 and the belt 12 are again free to moveas described before.

As previously explained, the cm cam 52 and the slide 2 34 will move as aunit if the belt 12 is slowly pulled out of the retractor and the cam 52will move relative to the slide 34 driving the pawls 40 into the racks32 if the belt is pulled out of the retractor above a predetermined rateof acceleration. The point at which the rate of acceleration of the belt12 causes the relative movement, rather than the unit movement, isvariable but dependent on such factors as the friction between the cam52 and the slide 34, the friction between their respective runners 62and 36 and the channel 26 and cover 82, the angle of engagement of thecam surfaces 56 and the camming surfaces 44 and the tension of spring48. in any particular design, the variables of friction and engagementangle are fixed so that to vary the point of change from unit movementof relative movement, the tension of spring 48 must be varied. lln orderto obtain a retractor which will slide up to a desired limit ofacceleration rate and lock at an acceleration rate greater than thedesired limit, the spring rate of spring 48 must be adjusted. Thisadjustment may be either by calculation or trial and error to obtain theproper combination of the friction, cam angle and spring rate whichproduces the desired limit of acceleration to change from sliding tolocking of belt Referring now to FIG. 7, a second embodiment of thisinvention is shown. This embodiment differs from the previous embodimentonly in the pawls and 92 which have meshing gear teeth 94 and 96. Teeth94 and 96 insure that any movement of one pawl results in simultaneousmovement of the other pawl into or out of engagement with a respectiverack 32. The teeth 94 and 96 thus insure a more evenly distributedlocking force between the pawls 90 and 92.

Although various forms of this invention have been described in detail,it will appear obvious to those skilled in the art that various othermodifications may be made without departing from the scope of thisinvention.

lclaim:

1. An elongated retractor for a restraint belt comprising a support,elongated rack means secured to the support, a slide, means mounting theslide on the support for reciprocal movement relative to the rack means,pawl means pivotally mounted to the slide for reciprocal movementtherewith relative to the rack means and pivotal movement relativethereto into engagement with the rack means to releasably secure theslide to the rack means, biasing means normally holding the pawl meansout 'of engagement with the rack means, cam means mounted on the slidefor movement therewith and reciprocal movement relative thereto intoengagement with the pawl means to move the pawl means into engagementwith the rack means against the action of the holding means, relativemovement control means for controlling said cam means and said slide tomove as a unit on application of an acceleration to the cam means belowa predetermined limit and also to permit said cam means to move relativeto said slide on application of an acceleration to the cam means greaterthan said predetermined limit, and means for applying acceleration froma restraint belt to the cam means.

2. An elongated retractor for a restraint belt comprising a support, apair of spaced elongated racks mounted to the support, a slide, meansmounting the slide on the support for reciprocal movement relative tothe racks, a pair of pawls pivoted to the slide for reciprocal movementtherewith relative to the racks and pivotal movement relative theretointo engagement with a respective rack to releasably secure the slide tothe racks, holding means normally holding the pawls out of engagementwith the racks, cam means mounted to the slide for movement therewithand reciprocal movement relative thereto into engagement with the pawlsto move the pawls into engagement with the racks against the action ofthe holding means, friction means for providing a frictional connectionbetween said cam means and said slide to move said cam means and saidslide as a unit on application of an acceleration to the cam means belowa predetermined limit and also to permit said cam means to move relativeto the slide on application of an acceleration greater than thepredetermined limit, and means for applying acceleration from arestraint belt to the cam means.

3. A retractor as recited in claim 2 wherein gear means interconnect thepawls for movement of the other pawl upon movement of one pawl.

4. A retractor as recited in claim 2 wherein the cam means wedges thepawls oppositely into their respective racks.

5. An elongated retractor for a restraint belt comprising a support, apair of elongated racks mounted to the support in a spaced relationship,a slide including a flat portion and runners engaging the support forreciprocal movement relative to the racks and for spacing the flatportion of the slide from the support, a pair of pawls pivotally mountedto the flat portion for reciprocal movement with the slide and swingingmovement thereto into engagement with the respective rack to releasablysecure the slide to the rack, spring means mounted between the pawlsnormally holding the pawls out of engagement with the rack, stop meansmounted to the slide for positioning the pawls on the flat portion, acam frictionally engaging the flat portion of the slide 'for causingmovement therewith and also for permitting reciprocal movement relativethereto into engagement with the pawls to move the pawls into the racksagainst the action of the spring means, clamp means for clamping saidcam and said slide to control the frictional engagement therebetween tomove the cam and the slide as a unit upon the application of anacceleration to the cam below a predetermined limit and also to permitsaid cam to slide on the slide upon application of an accelerationgreater than the predetermined limit to pivot the pawls, and meansapplying acceleration of the restraint belt to the cam means. saidrestraint belt passing under the slide. around the cam means and overthe slide.

6. A retractor as recited in claim 5 wherein the clamp means comprises aslot in the cam fastening means through the slot clamping the cam to theslide, the slot being sufficiently long to allow the cam to move thepawls into engagement with their

1. An elongated retractor for a restraint belt comprising a support,elongated rack means secured to the support, a slide, means mounting theslide on the support for reciprocal movement relative to the rack means,pawl means pivotally mounted to the slide for reciprocal movementtherewith relative to the rack means and pivotal movement relativethereto into engagement with the rack means to releasably secure theslide to the rack means, biasing means normally holding the pawl meansout of engagement with the rack means, cam means mounted on the slidefor movement therewith and reciprocal movement relative thereto intoengagement with the pawl means to move the pawl means into engagementwith the rack means against the action of the holding means, relativemovement control means for controlling said cam means and said slide tomove as a unit on application of an acceleration to the cam means belowa predetermined limit and also to permit said cam means to move relativeto said slide on application of an acceleration to the cam means greaterthan said predetermined limit, and means for applying acceleration froma restraint belt to the cam means.
 2. An elongated retractor for arestraint belt comprising a support, a pair of spaced elongated racksmounted to the support, a slide, means mounting the slide on the supportfor reciprocal movement relative to the racks, a pair of pawls pivotedto the slide for reciprocal movement therewith relative to the racks andpivotal movement relative thereto into engagement with a respective rackto releasably secure the slide to the racks, holding means normallyholding the pawls out of engagement with the racks, cam means mounted tothe slide for movement therewith and reciprocal movement relativethereto into engagement with the pawls to move the pawls into engagementwith the racks against the action of the holding means, friction meansfor providing a frictional connection between said cam means and saidslide to move said cam means and said slide as a unit on application ofan acceleration to the cam means below a predetermined limit and also topermit said cam means to move relative to the slide on application of anacceleration greater than the predetermined limit, and means forapplying acceleration from a restraint belt to the cam means.
 3. Aretractor as recited in claim 2 wherein gear means interconnect thepawls for movement of the other pawl upon movement of one pawl.
 4. Aretractor as recited in claim 2 wherein the cam means wedges the pawlsoppositely into their respective racks.
 5. An elongated retractor for arestraint belt comprising a support, a pair of elongated racks mountedto the support in a spaced relationship, a slide including a flatportion and runners engaging the support for reciprocal movementrelative to the racks and for spacing the flat portion of the slide fromthe support, a pair of pawls pivotally mounted to the flat portion forreciprocal movement with the slide and swinging movement thereto intoengagement with the respective rack to releasably secure the slide tothe rack, spring means mounted between the pawls normally holding thepawls out of engagement with the rack, stop means mounted to the slidefor positioning the pawls on the flat portion, a cam frictionallyengaging the flat portion of the slide for causing movement therewithand also for permitting reciprocal movement relative thereto intoengagement with the pawls to move the pawls into the racks against theaction of the spring means, clamp means for clamping said cam and saidslide to control the frictional engagement therebetween to move the camand the slide as a unit upon the application of an acceleration to thecam belOw a predetermined limit and also to permit said cam to slide onthe slide upon application of an acceleration greater than thepredetermined limit to pivot the pawls, and means applying accelerationof the restraint belt to the cam means, said restraint belt passingunder the slide, around the cam means and over the slide.
 6. A retractoras recited in claim 5 wherein the clamp means comprises a slot in thecam fastening means through the slot clamping the cam to the slide, theslot being sufficiently long to allow the cam to move the pawls intoengagement with their respective racks before the fastening meansengages the end of the slot whereby the load of stopping the cam istaken by the pawls rather than by the fastening means.